Method and facility for producing separator for use in polymer electrolyte fuel cell

ABSTRACT

A material to be formed, which is uncoiled by an uncoiler from a coil while controlled against meandering, is adjusted in inclination angle by an approach angle adjuster and guided into a separator-forming mill. The material to be formed is introduced and pressurized between rolls in the mill so as to continuously form a separator. The separator formed by the mill is discharged and tension controlled by a pinch roll device with opposite widthwise ends of the separator being pinched. The separator discharged by the pinch roll device is cut without stopping the same by a flying shear at portions with no passages formed.

TECHNICAL FIELD

The present invention relates to a method and a facility for producing aseparator for use in a polymer electrolyte fuel cell.

BACKGROUND ART

Generally, a polymer electrolyte fuel cell uses as fuel pure hydrogen ora hydrogen gas acquired by reforming alcohols, and generates electricityby electrochemically controlling a reaction of the hydrogen with oxygenin the air.

The polymer electrolyte fuel cell, which uses a solid, organic, hydrogenion permselective membrane as an electrolyte, can be compactified ascompared to conventional alkaline, phosphoric acid, molten carbonate,solid oxide or other fuel cells using an aqueous or fused saltelectrolyte or other fluid medium as an electrolyte, and is underdevelopment for electric vehicles and other applications.

The polymer electrolyte fuel cell used, as shown in FIG. 1, has cells 5each of which is of a sandwich structure provided by overlapping aseparator 1 with formed convexes and concaves 1 a and 1 b, a hydrogenelectrode 2, a polyelectrolyte membrane 3, an air (oxygen) electrode 4and a separator 1 with formed convexes and concaves 1 a and 1 b. Anumber of cells 5 are stacked into a stack 6 to provide a hydrogenpassage 7 defined by the separator 1 and the hydrogen electrode 2 incontact therewith, an air (oxygen) passage 8 defined by the separator 1and the air electrode 4 in contact therewith and a cooling water passage9 defined by the overlapped separators 1.

It is conventionally assumed that the separator 1 has a flat margin anda central bulge with a number of convexes and concaves 1 a and 1 bformed by press forming. However, actually attempted processing of amaterial made of sheet metal to be formed reveals that the press forminginto the shape described above has difficulty since ductile fracture mayoccur in the bulge with the convexes and concaves 1 a and 1 b. Moreover,attempt of mass producing the separators 1 by press forming willproblematically reduce the production efficiency.

In order to overcome the problems, it is recently proposed to oppositelyarrange a pair of rolls having surfaces with forming areas with createdconvexes and concaves and to introduce and pressurize a material made ofsheet metal to be formed between the rolls, thereby continuouslyproducing a separator 1 with passages (hydrogen, air and cooling waterpassages 7, 8 and 9) formed correspondingly to the concaves and convexesof the rolls.

A state-of-the-art technology of an apparatus for producing a separator1 for use in a polymer electrolyte fuel cell as shown in FIG. 1 isdisclosed, for example, in Patent Literature 1.

CITATION LIST Patent Literature

-   Patent Literature 1: JP 2002-190305A

SUMMARY OF INVENTION Technical Problems

However, it has been still demanded to form a material made of stainlesssteel or other sheet metal to be formed more and more thinly (to athickness of 0.1 mm or so) and accurately for the separator 1, andtherefore an urgent need is to develop a method and a facility forproducing the same.

The invention was made in view of the above and has its object toprovide a method and a facility for producing a separator for use in apolymer electrolyte fuel cell capable of accurately forming a materialmade of sheet metal to be formed without deteriorated productionefficiency and efficiently producing a highly accurate separator.

Solution to Problems

The invention is directed to a method for producing a separator for usein a polymer electrolyte fuel cell, which comprises adjusting andguiding a material to be formed, which is uncoiled by an uncoiler from acoil while controlled against meandering, in inclination angle by anapproach angle adjuster into a separator-forming mill, introducing andpressurizing said material to be formed between a pair of rolls in saidseparator-forming mill, said rolls being vertically oppositely arrangedto each other and each having circumferentially alternately a formingarea with concaves and convexes created on a surface and a non-formingarea with no concaves and convexes to continuously form a separatorhaving passages created correspondingly to said concaves and saidconvexes, discharging and tension controlling the separator formed bysaid separator-forming mill by a pinch roll device with oppositewidthwise ends of the separator being pinched, and cutting the separatordischarged by the pinch roll device without stopping the same by aflying shear at portions with no passages formed.

The invention is also directed to a facility for producing a separatorfor use in a polymer electrolyte fuel cell, comprising

an uncoiler capable of uncoiling a coil of a material to be formed whilecontrolling the same against meandering,

an approach angle adjuster capable of adjusting in inclination angle thematerial uncoiled from the coil by said uncoiler,

a separator-forming mill with a pair of rolls vertically oppositelyarranged to each other and each having circumferentially alternately aforming area with concaves and convexes created on a surface and anon-forming area with no concaves and convexes, the material adjusted ininclination angle by said approach angle adjuster being introduced andpressurized between said rolls for continuous formation of the separatorhaving passages created correspondingly to said concaves and saidconvexes,

a pinch roll device capable of discharging and tension controlling theseparator formed by said separator-forming mill with opposite widthwiseends of the separator being pinched, and

a flying shear for cutting the separator discharged by said pinch rolldevice at portions with no passages formed without stopping the same.

According to the above-mentioned means, the following effects areacquired.

The material which is uncoiled from the coil by the uncoiler whilecontrolled against meandering is adjusted in inclination angle by theapproach angle adjuster and guided to the separator-forming mill; thematerial is introduced and pressurized between the paired rolls in theseparator-forming mill, which are vertically oppositely arranged to eachother and each of which has circumferentially alternately forming areawith the concaves and convexes created on the surface and thenon-forming area with no concaves and convexes, to continuously form theseparator having passages created correspondingly to the concaves andthe convexes; the separator formed by the separator-forming mill isdischarged and tension controlled by the pinch roll device with oppositewidthwise ends of the separator being pinched; the separator dischargedby the pinch roll device is cut, without stopping the same, by theflying shear at portions with no passages formed. Thus, the materialmade of extremely thin sheet metal is reliably formed and cut to enableefficient producing of the separators satisfying a requested accuracy.

In the facility for producing the separator for use in a polymerelectrolyte fuel cell, it is preferable that edge conveying guiderollers which support opposite widthwise ends of the separator arearranged on an exit side of the separator-forming mill for stableconveying of the separator having the passages corresponding to theconcaves and the convexes.

In the facility for producing the separator for use in a polymerelectrolyte fuel cell, said separator-forming mill may include

push-up cylinders capable of adjusting a gap between said rolls,

full-time play eliminating cylinders arranged between a housing and mainbearing axle boxes for said rolls to eliminate plays in the vertical andhorizontal directions,

auxiliary bearings fitted to necks of said rolls, non-forming-time playeliminating cylinders arranged between said auxiliary bearings toeliminate a play between said rolls and said main bearings,

load sensors for sensing forming loads, and

a controller which outputs operational signals to said push-upcylinders, said full-time play eliminating cylinders and saidnon-forming-time play eliminating cylinders, respectively, on the basisof the forming loads sensed by the load sensors to repeatedly performthe elimination of the play between the rolls and the main bearings inthe non-forming area and the forming of the material in the forming areawhile the play between the housing and the main bearing axle boxes forthe rolls is always eliminated. Thus, with the play between the housingand the main bearing axle boxes for the rolls in the separator-formingmill being eliminated by the operation of the full-time play eliminatingcylinders and the play between the rolls and the main bearings beingeliminated by the operation of the non-forming-time play eliminatingcylinders, the gap between the rolls can be accurately retained at thesetting value and, even if the material is made of extremely thin sheetmetal, the accuracy required for the forming is acquired to enable theefficient producing of the separator.

In the facility for producing the separator for use in a polymerelectrolyte fuel cell, it is preferable that roll shafts of the rollsare directly coupled to separate servo motors through reduction gearsincluding their respective strain wave gearing mechanisms and thereduction gears are directly coupled to the corresponding main bearingaxle boxes for transmitting a rotative force to the rolls with a play ofa rotative power transmission system minimized in the rotationaldirection.

Advantageous Effects of Invention

A method and a facility for producing a separator for use in a polymerelectrolyte fuel cell of the invention can achieve excellent effectsthat a material made of sheet metal to be formed can be accuratelyformed without deteriorated production efficiency and a highly accurateseparator can be efficiently produced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an enlarged sectional view of an example of a polymerelectrolyte fuel cell;

FIG. 2 is a schematic of an overall configuration of an embodiment ofthe invention;

FIG. 3 is an overall plan view of the embodiment of the invention;

FIG. 4 is a sectional side view of a separator-forming mill in theembodiment of the invention;

FIG. 5 is a sectional view of rolls of the separator-forming mill in theembodiment of the invention, corresponding to a sectional view takenalong V-V in FIG. 4;

FIG. 6 is a diagram of full-time play eliminating cylinders whicheliminate play between the rolls and main bearings in theseparator-forming mill in the embodiment of the invention, correspondingto an arrow view taken along VI-VI in FIG. 4;

FIG. 7 is a diagram of non-forming-time play eliminating cylinders whicheliminate a play between the rolls and the main bearings in theseparator-forming mill in the embodiment of the invention as well asauxiliary bearings, corresponding to an arrow view taken along VII-VIIin FIG. 4;

FIG. 8 a is an elevation for explaining a principle of a strain wavegearing mechanism of a reduction gear applied to the separator-formingmill of FIG. 4, showing a state before starting rotation of a wavegenerator;

FIG. 8 b is an elevation for explaining the principle of the strain wavegearing mechanism of the reduction gear applied to the separator-formingmill of FIG. 4, showing a state when the wave generator is rotatedclockwise by 90 degrees;

FIG. 8 c is an elevation for explaining the principle of the strain wavegearing mechanism of the reduction gear applied to the separator-formingmill of FIG. 4, showing a state when the wave generator is rotatedclockwise by 360 degrees; and

FIG. 9 is a control chart of a relationship among outputs of the loadsensors, operational states of full-time, non-forming-time playeliminating and push-up cylinders and a gap between the rolls in theseparator-forming mill before starting forming of the material and informing and non-forming areas in the embodiment of the invention.

DESCRIPTION OF EMBODIMENT

An embodiment of the invention will be described with reference to theaccompanying drawings.

FIGS. 2 and 3 show the embodiment of the invention comprising anuncoiler 40 capable of uncoiling a coil 1B of a material 1A to be formedwhile controlling the same against meandering, an approach angleadjuster 50 capable of adjusting in inclination angle the material 1Auncoiled from the coil 1B by the uncoiler 40, a separator-forming mill60 which continuously forms a separator 1 (see FIG. 1) with formedpassages (hydrogen, air and cooling water passages 7, 8 and 9) byintroducing and pressurizing the material 1A adjusted in inclinationangle by the adjuster 50 between a pair of rolls 13 describedhereinafter, a pinch roll device 70 capable of discharging and tensioncontrolling the separator 1 formed by the mill 60 with oppositewidthwise ends of the separator being pinched, and a flying shear 80which cuts the separator 1 discharged by the pinch roll device 70 atportions with no passage formed without stopping the separator, thusproviding a facility for producing a separator for use in a polymerelectrolyte fuel cell.

In this embodiment, arranged on an exit side of the separator-formingmill 60 are edge conveying guide rollers 90 which support oppositewidthwise ends of the separator 1.

The uncoiler 40 is constructed, as shown in FIGS. 2 and 3, such thatguide rails 41 are laid down to extend horizontally and perpendicular toa travel direction of the material 1A and a base plate 42 is arranged onand slidably along the rails by telescopic operation of a slide actuator43. Arranged on the base plate 42 are an uncoiler body 44 which uncoilsthe coil 1B, a brake device 45 which controls torque of the uncoilerbody 44 during uncoiling of the material 1A and an uncoiling guideroller 46 which discharges the material 1A uncoiled from the coil 1B inthe uncoiler body 44. Control of the material 1A against the meanderingis performed by operating the slide actuator 43 for the horizontalsliding of the base plate 42 perpendicular to the travel direction ofthe material 1A; and tension control of the material 1A is performed byoperating the brake device 45 for torque control of the uncoiler body 44during uncoiling of the material 1A.

The approach angle adjuster 50 is constructed, as shown in FIGS. 2 and3, by a pair of vertically oppositely arranged adjusting rolls 52 whichare rotatably supported by a housing 51 and are vertically movable byoperating an elevating actuator 53. The inclination angle of thematerial 1A is adjustable by vertically moving the adjusting rolls 52with the material 1A being introduced therebetween.

The pinch roll device 70 is constructed, as shown in FIGS. 2 and 3, by apair of vertically oppositely arranged pinch rolls 72 each havingopposite widthwise ends with a diameter greater than that of a middleportion of the pinch roll. The pinch rolls are supported by a pinchhousing 71 such that their rotational speed is adjustable by operating aservo motor 73 and their pinching pressure is adjustable by operating apressurizing cylinder 74. The separator 1 formed by theseparator-forming mill 60 is discharged and tension controlled by thepinch roll device with opposite widthwise ends of the separator beingpinched by the pinch rolls 72.

The flying shear 80 is constructed, as shown in FIGS. 2 and 3, such thatguide rails 82 are laid down on a fixed pedestal 81 to extend in thetravel direction of the separator 1, and a moving table 83 with a shearbody 87 arranged thereon is slidable along the guide rails 82 by movinga nut 86 through rotary drive of a ball screw 85 by a servo motor 84.Thus, the separator 1 discharged by the pinch roll device 70 is adaptedto be cut with the shear body 87 without stopping the separator bysliding and operating the shear body 87 in synchronism with the travelspeed of the separator 1.

Arranged on an entry side of the approach angle adjuster 50 is anoncontact photosensor 100 which senses the inclination angle and anymeandering of the material 1A to be formed.

FIGS. 4 to 9 are views relating to the separator-forming mill 60 in theembodiment of the invention. Reference numeral 10 denotes a housing; 11,main bearing axle boxes arranged in the housing 10; 12, main bearingsarranged in the main bearing axle boxes 11; and 13, a pair of rollsarranged vertically oppositely to each other and rotatably supported bythe main bearings 12 to the housing 10. As shown in FIGS. 4 and 5, theroll 13 has circumferentially alternately a forming area with concaves14 a and convexes 14 b created on a surface and a non-forming area withno concaves 14 a and convexes 14 b.

In the embodiment, the forming and non-forming areas arecircumferentially alternately formed on the roll 13 by fitting twoarc-shaped dies 14 each having the forming area with the concaves 14 aand the convexes 14 b created on the surface onto a roll body 13 a ofthe roll 13 with keys 15 and bolts or other fastening members 16.

Arranged in a lower portion of the housing 10 are push-up cylinders 17capable of adjusting a gap between the rolls 13 by pushing up and downthe main bearing axle boxes 11 of the roll 13 on the lower side.Arranged between the housing 10 and the main bearing axle boxes 11 forthe rolls 13 are full-time play eliminating cylinders 18 and 19 (seeFIGS. 4 and 6) eliminating plays in vertical and horizontal directions.Fitted to necks 13 b of the rolls 13 are auxiliary bearings 20. Arrangedbetween the auxiliary bearings 20 are non-forming time play eliminatingcylinders 21 (see FIGS. 4 and 7) eliminating play between the rolls 13and the main bearings 12. Arranged in an upper portion of the housing 10are load cells or other load sensors 23 sensing forming loads 23 a. Acontroller 24 is arranged to output operational signals 17 a, 18 a, 19 aand 21 a to the push-up cylinders 17, the full-time play eliminatingcylinders 18 and 19 and the non-forming-time play eliminating cylinders21, respectively, on the basis of the forming loads 23 a sensed by theload sensors 23.

The non-forming-time play eliminating cylinder 21 is interposed betweenhalf-divided auxiliary bearing covers 22 attached to cover the outercircumferences of the auxiliary bearings 20.

Roll shafts 13 c of the respective rolls 13 are directly coupled toseparate servo motors 26 through reduction gears 25 with theirrespective strain wave gearing mechanisms, which are so-called harmonicdrives (registered trademark), and the reduction gears 25 are directlycoupled to the corresponding main bearing axle boxes 11.

As shown in FIGS. 8 a to 8 c, the reduction gear 25 with the strain wavegearing mechanism comprises a wave generator 27 having an ellipticalouter circumference, an elastically deformable flexspline 29 having anouter circumference with a number of external teeth and fitted over thewave generator 27 via a bearing 28, circumferentially deflectedpositions of the flexspline 29 sequentially changing due to rotation ofthe wave generator 27 as shown in FIGS. 8 b and 8 c, and a non-rotativecircular spline 30 located circumferentially of the flexspline 29 andhaving internal teeth fitted with the external teeth of the flexspline29, positions of the internal teeth of the circular spline fitted withthe external teeth of the flexspline being changed as the deflectedpositions of the flexspline 29 change. The wave generator 27 has a shafthole 27 a into which a shaft 26 a of the servo motor 26 is fitted (seeFIG. 4); and the flexspline 29 is connected with the roll shaft 13 c ofthe roll 13. The number of the external teeth of the flexspline 29 isseveral fewer than that of the internal teeth of the circular spline 30.

For example, when the wave generator 27 rotates clockwise in FIG. 8 adue to the drive of the servo motor 26, the flexspline 29 elasticallydeforms; the external teeth of the flexspline 29 engage with theinternal teeth of the circular spline 30 at long axis portions of theellipse of the wave generator 27, the external teeth of the flexspline29 completely departing from the internal teeth of the circularspline 30at short axis portions of the ellipse of the wave generator 27; as aresult, the engaging positions between the external teeth of theflexspline 29 and the internal teeth of the circular spline 30sequentially move circumferentially (clockwise) (see FIG. 8 b); and whenthe wave generator 27 rotates once, the engaging positions between theexternal teeth of the flexspline 29 and the internal teeth of thecircularspline 30 are moved from the positions at the start of rotation(see FIG. 8 c). As a result, the flexspline 29 is located short of thepositions at the start of rotation by the number of the external teethless than the number of the internal teeth of the circularspline 30 (seeFIG. 8 c) and, therefore, the flexspline 29 is moved in the directionopposite to the rotational direction of the wave generator 27 (in thecounterclockwise direction in FIG. 8 c), which is picked up as arotational output by the roll shaft 13 c of the roll 13.

Backlash of the reduction gear 25 itself, which directly affectsrotational variations of the roll 13, must be minimal. Since thereduction gear 25 with the strain wave gearing mechanism is a reductiongear having extremely minimal backlash as described above, plays of therotative power system (variation in rotative phase difference) arereduced by the reduction gear 25 to a negligible level in the invention.

Further in the embodiment, as shown in FIG. 9, before starting theforming, the controller 24 outputs the operational signals 18 a and 19 awhich set the setting pressure of the full-time play eliminatingcylinders 18 and 19 to P₀; with plays in the vertical and horizontaldirections being thus eliminated between the housing 10 and the mainbearing axle boxes 11 for the rolls 13, the controller 24 outputs theoperational signals 17 a which retract the push-up cylinders 17 to makea gap between the rolls 13 greater than a setting value g_(a), andoutputs the operational signals 21 a which set the setting pressure ofthe non-forming-time play eliminating cylinders 21 to P₀ to eliminateplays between the rolls 13 and the main bearings 12; in this state, thecontroller 24 outputs the operational signals 17 a which set theextension amount of the push-up cylinders 17 to S_(t) to set the gapbetween the rolls 13 to the setting value g_(a). When the material 1Amade of sheet metal to be formed (see FIG. 5) is introduced between therolls 13 and the forming loads 23 a are generated and sensed by the loadsensors 23, it is determined that the material 1A enters into theforming area and the controller 24 outputs the operational signals 21 awhich change the setting pressures of the non-forming-time playeliminating cylinders 21 from P₀ to 0 to cause the forming of thematerial 1A. When the forming loads 23 a turn to zero, it is determinedthat the material 1A enters into the non-forming area and the controller24 outputs the operational signals 17 a which retract the push-upcylinders 17 to change the extension amount from S_(t) to S₁ to increasethe gap between the rolls 13 into g₁ which is greater than the settingvalue g_(a), and outputs the operational signals 21 a which set thesetting pressure of the non-forming-time play eliminating cylinders 21to P₀ to eliminate the play between the rolls 13 and the main bearings12; the controller 24 outputs the operational signals 17 a whichincrease the extension amount of the push-up cylinders 17 from S₁ toS_(t) again to set the gap between the rolls 13 to the setting valueg_(a). When the forming loads 23 a are generated, it is determined thatthe material 1A enters into the forming area and the controller 24outputs the operational signals 21 a which change the setting pressureof the non-forming-time play eliminating cylinders 21 from P₀ to 0 tocause the forming of the material 1A. Subsequently, the elimination ofthe play between the rolls 13 and the main bearings 12 in thenon-forming area and the forming of the material 1A in the forming areaare repeatedly performed while the plays between the housing 10 and themain bearing axle boxes 11 for the rolls 13 are always eliminated.

An operation of the embodiment will be described.

As shown in FIGS. 2 and 3, the material 1A uncoiled from the coil 1B bythe uncoiler 40 while controlled against meandering is adjusted ininclination angle by the approach angle adjuster 50 and guided to theseparator-forming mill 60. The material 1A is introduced and pressurizedbetween vertically oppositely arranged, paired rolls 13 in theseparator-forming mill 60 having circumferentially alternately theforming area with the concaves 14 a and the convexes 14 b created on thesurface and the non-forming area with no concaves 14 a and convexes 14 bto continuously form the separator 1 (see FIG. 1) having passages (thehydrogen, air and cooling water passages 7, 8 and 9) createdcorrespondingly to the concaves 14 a and the convexes 14 b. Theseparator 1 formed by the separator-forming mill 60 is discharged andtension controlled by the pinch roll device 70 with opposite widthwiseends of the separator being pinched. The separator 1 discharged by thepinch roll device 70 is cut without stopping the same by the flyingshear 80 at portions with no passage formed. Thus, the material made ofextremely thin sheet metal is reliably formed and cut to enableefficient production of the separators 1 satisfying a requestedaccuracy.

In the facility for producing the separator for use in a polymerelectrolyte fuel cell shown in FIGS. 2 and 3, the edge conveying guiderollers 90 supporting the opposite widthwise ends of the separator 1 arearranged on the exit side of the separator-forming mill 60, so that theseparator 1 can be stably conveyed.

Next, an operation of the separator-forming mill 60 will be describedhereinafter in detail.

First, in a preparatory stage before starting the forming, thecontroller 24 outputs the operational signals 18 a, 19 a which set thesetting pressure of the full-time play eliminating cylinders 18 and 19to P₀; with the plays in the vertical and horizontal directions beingthus eliminated between the housing 10 and the main bearing axle boxes11 for the rolls, the controller 24 outputs the operational signals 17 awhich retract the push-up cylinder 17 to retain the gap between therolls 13 greater than the setting value g_(a), and outputs theoperational signals 21 a which set the setting pressure of thenon-forming-time play eliminating cylinders 21 to P₀ to eliminate theplays between the rolls 13 and the main bearings 12; in this state, thecontroller 24 outputs the operational signals 17 a which set theextension amount of the push-up cylinders 17 to S_(t) to set the gapbetween the rolls 13 to the setting value g_(a).

When the material 1A made of sheet metal to be formed (see FIG. 5) issubsequently introduced between the rolls 13 to start the forming, theforming loads 23 a sensed by the load sensors 23 jumps up; it isdetermined at this point that the material 1A enters into the formingarea and the controller 24 outputs the operational signals 21 a whichchange the setting pressure of the non-forming-time play eliminatingcylinders 21 from P₀ to 0 to cause the forming of the material 1A.

When the forming load 23 a subsequently turns to zero, it is determinedthat the material 1A enters into the non-forming area and the controller24 outputs the operational signals 17 a which retract the push-upcylinders 17 to change the extension amount from S_(t) to S₁ to expandthe gap between the rolls 13 to g₁ which is greater than the settingvalue g_(a), and outputs the operational signals 21 a which set thesetting pressure of the non-forming-time play eliminating cylinders 21to P₀ to eliminate the play between the rolls 13 and the main bearings12; and the controller 24 outputs the operational signals 17 a whichincrease the extension amount of the push-up cylinders 17 from S₁ toS_(t) again to set the gap between the rolls 13 to the setting valueg_(a).

When the forming load 23 a is generated, it is determined that thematerial 1A enters into the forming area and the controller 24 outputsthe operational signals 21 a which change the setting pressure of thenon-forming-time play eliminating cylinders 21 from P₀ to 0 to cause theforming of the material 1A. Subsequently, the elimination of the playbetween the rolls 13 and the main bearings 12 in the non-forming areaand the forming of the material 1A in the forming area are repeatedlyperformed while the plays between the housing 10 and the main bearingaxle boxes 11 for the rolls 13 is always eliminated.

In this way, the play between the housing 10 and the main bearing axleboxes 11 for the rolls 13 is eliminated by the operation of thefull-time play eliminating cylinders 18 and 19; the play between therolls 13 and the main bearings 12 is eliminated by the operation of thenon-forming-time play eliminating cylinders 21; and the gap between therolls 13 can be accurately retained at the setting value g_(a). As aresult, even if the material 1A is made of extremely very thin sheetmetal, the accuracy required for the forming is acquired to enable theefficient producing of the separators 1 (see FIG. 1) having passages(the hydrogen, air and cooling water passages 7, 8 and 9) highlyaccurately created correspondingly to the concaves 14 a and the convexes14 b.

Moreover the roll shafts 13 c of the rolls 13 are directly coupled tothe separate servo motors 26 through the reduction gears 25 includingtheir respective strain wave gearing mechanisms and the reduction gears25 are directly coupled to the corresponding main bearing axle boxes 11.Thus, when the servo motors 26 are driven, the rotative powers of theservo motors 26 are transmitted through the shafts 26 a to the reductiongears 25 including the strain wave gearing mechanisms, decelerated andtransmitted to the roll shafts 13 c of the rolls 13 and, as a result,the rolls 13 are independently rotated. Since the servo motors 26 have alower value of speed variance of the order of ±0.01% and therefore havereduced vibrations and since the shafts 26 a of the servo motors 26 aredirectly coupled to the reduction gears 25 including the strain wavegearing mechanisms and no play is generated by, for example, a backlashof a gear or a clearance of a joint, rotative forces with reducedvibration can be transmitted to the reduction gears 25 including thestrain wave gearing mechanisms. Since the reduction gear 25 includingthe strain wave gearing mechanism is a reduction gear having anextremely minimal backlash and therefore the rotative force of the servomotor 26 is transmitted to the roll 13 with vibrations suppressed asmuch as possible, the roll 13 is stably rotated without vibrations.

Pattern control may be employed such that a longitudinal forming amountof the material 1A becomes constant while any different push-in amountin the forming area is allowed as a function of a different elasticdeformation in the forming area due to different fitting of thearc-shaped die 14. For example, in the case of the die 14 fitted tightlyto a flattened outer circumferential portion of the roll 13 as shown inFIG. 5 and when the material 1A is formed at a die central portion justbelow the key 15 causing greater depressing deformation due to lowerspring constant of the die portion, the screw-down or depression may beperformed in a convenient pushing pattern so as to increase theextension amount of the push-up cylinders 17 beyond S_(t) and decreasethe gap between the rolls 13 below the usual setting value g_(a).

When a facility for producing a separator for use in a polymerelectrolyte fuel cell is used which includes the uncoiler 40, theapproach angle adjuster 50, the separator-forming mill 60, the pinchroll device 70, the flying shear 80 and the edge conveying guide rollers90 as described above, the material 1A made of sheet metal to be formedcan be accurately formed without deteriorated production efficiency andthe highly accurate separators 1 may be efficiently manufactured.

It is to be understood that a method and a facility for producing aseparator for use in a polymer electrolyte fuel cell are not limited tothe above embodiment and that various changes and modifications may bemade without departing from the scope of the invention.

REFERENCE SIGNS LIST

-   1 separator-   1A material to be formed-   1B coil-   1 a convex-   1 b concave-   7 hydrogen passage (passage)-   8 air passage (passage)-   9 cooling water passage (passage)-   10 housing-   11 main bearing axle box-   12 main bearing-   13 roll-   13 a roll body-   13 b neck-   13 c roll shaft-   14 die-   14 a concave-   14 b convex-   17 push-up cylinder-   17 a operational signal-   18 full-time play eliminating cylinder-   18 a operational signal-   19 full-time play eliminating cylinder-   19 a operational signal-   20 auxiliary bearing-   21 non-forming-time play eliminating cylinder-   21 a operational signal-   22 auxiliary bearing cover-   23 load sensor-   23 a forming load-   24 controller-   25 reduction gear-   26 servo motor-   27 wave generator-   29 flexspline-   30 circular spline-   40 uncoiler-   50 approach angle adjuster-   60 separator-forming mill-   70 pinch roll device-   80 flying shear-   90 edge conveying guide roller

The invention claimed is:
 1. A method for producing a separator for usein a polymer electrolyte fuel cell, comprising: adjusting and guiding amaterial to be formed, which is uncoiled by an uncoiler from a coilwhile controlled against meandering, in inclination angle by an approachangle adjuster into a separator-forming mill, introducing andpressurizing said material to be formed between a pair of rolls in saidseparator-forming mill, said rolls being vertically oppositely arrangedto each other and each having circumferentially alternately a formingarea with concaves and convexes created on a surface and a non-formingarea with no concaves and convexes to continuously form a separatorhaving passages created correspondingly to said concaves and saidconvexes, discharging and tension controlling the separator formed bysaid separator-forming mill by a pinch roll device with oppositewidthwise ends of the separator being pinched, and cutting the separatordischarged by the pinch roll device without stopping the same by aflying shear at portions with no passages formed.
 2. A method forproducing a separator for use in a polymer electrolyte fuel cell asclaimed in claim 1, wherein said separator-forming mill includes push-upcylinders capable of adjusting a gap between said rolls, full-time playeliminating cylinders arranged between a housing and main bearing axleboxes for said rolls to eliminate plays in the vertical and horizontaldirections, auxiliary bearings fitted to necks of said rolls,non-forming-time play eliminating cylinders arranged between saidauxiliary bearings to eliminate a play between said rolls and said mainbearings, and load sensors for sensing forming loads, and wherein saidintroducing and pressurizing said material to be formed in saidseparator-forming mill includes outputting operational signals to saidpush-up cylinders, said full-time play eliminating cylinders and saidnon-forming-time play eliminating cylinders, respectively, on the basisof the forming loads sensed by the load sensors to repeatedly performthe elimination of the play between the rolls and the main bearings inthe non-forming area and the forming of the material in the forming areawhile the play between the housing and the main bearing axle boxes forthe rolls is eliminated.
 3. A method for producing a separator for usein a polymer electrolyte fuel cell as claimed in claim 2, wherein rollshafts of said rolls are directly coupled to separate servo motorsthrough reduction gears including their respective strain wave gearingmechanisms and the reduction gears are directly coupled to thecorresponding main bearing axle boxes.
 4. A facility for producing aseparator for use in a polymer electrolyte fuel cell, comprising: anuncoiler capable of uncoiling a coil of a material to be formed whilecontrolling the same against meandering, an approach angle adjustercapable of adjusting in inclination angle the material uncoiled from thecoil by said uncoiler, a separator-forming mill with a pair of rollsvertically oppositely arranged to each other and each havingcircumferentially alternately a forming area with concaves and convexescreated on a surface and a non-forming area with no concaves andconvexes, the material adjusted in inclination angle by said approachangle adjuster being introduced and pressurized between said rolls forcontinuous formation of the separator having passages createdcorrespondingly to said concaves and said convexes, a pinch roll devicecapable of discharging and tension controlling the separator formed bysaid separator-forming mill with opposite widthwise ends of theseparator being pinched, and a flying shear for cutting the separatordischarged by said pinch roll device at portions with no passages formedwithout stopping the same.
 5. A facility for producing a separator foruse in a polymer electrolyte fuel cell as claimed in claim 4, whereinedge conveying guide rollers for supporting opposite widthwise ends ofthe separator are arranged on an exit side of the separator-formingmill.
 6. A facility for producing a separator for use in a polymerelectrolyte fuel cell as claimed in claim 4, wherein saidseparator-forming mill includes push-up cylinders capable of adjusting agap between said rolls, full-time play eliminating cylinders arrangedbetween a housing and main bearing axle boxes for said rolls toeliminate plays in the vertical and horizontal directions, auxiliarybearings fitted to necks of said rolls, non-forming-time playeliminating cylinders arranged between said auxiliary bearings toeliminate a play between said rolls and said main bearings, load sensorsfor sensing forming loads, and a controller which outputs operationalsignals to said push-up cylinders, said full-time play eliminatingcylinders and said non-forming-time play eliminating cylinders,respectively, on the basis of the forming loads sensed by the loadsensors to repeatedly perform the elimination of the play between therolls and the main bearings in the non-forming area and the forming ofthe material in the forming area while the play between the housing andthe main bearing axle boxes for the rolls is eliminated.
 7. A facilityfor producing a separator for use in a polymer electrolyte fuel cell asclaimed in claim 6, wherein roll shafts of said rolls are directlycoupled to separate servo motors through reduction gears including theirrespective strain wave gearing mechanisms and the reduction gears aredirectly coupled to the corresponding main bearing axle boxes.